Tooth Decay

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Illustration of a tooth

This topic provides information on tooth decay and cavities. If you are looking for information on:

What is tooth decay?

Tooth decay is the process that results in a cavity (dental caries). It occurs when bacteria in your mouth make acids that eat away at a tooth. If not treated, tooth decay can cause pain, infection, and tooth loss.

See pictures of a tooth and tooth decay.

You can easily prevent tooth decay by brushing and flossing your teeth regularly, seeing your dentist for teeth cleaning and checkups, and avoiding foods that are high in sugar.

What causes tooth decay?

The combination of bacteria and food causes tooth decay. A clear, sticky substance called plaque that contains bacteria is always forming on your teeth and gums. As the bacteria feed on the sugars in the food you eat, they make acids. The acids attack the teeth for 20 minutes or more after eating. Over a period of time, these acids destroy tooth enamel, resulting in tooth decay.

What are the symptoms?

Tooth decay usually does not cause symptoms until you have a cavity or an infected tooth. When this occurs, a toothache is the most common symptom.

How is tooth decay diagnosed?

Your dentist diagnoses tooth decay by:

  • Asking questions about your past dental and medical problems and care.
  • Examining your teeth, using a pointed tool and a small mirror.
  • Taking X-rays of your teeth and mouth.

How is it treated?

Treatment for tooth decay depends on how bad it is. You may be able to reverse slight tooth decay by using fluoride. To fix cavities caused by mild tooth decay, your dentist will fill the cavities with another substance (fillings). For more severe tooth decay, you may need a crown or root canal. In extreme cases, your dentist may have to remove the tooth.

Frequently Asked Questions

Learning about tooth decay:

Being diagnosed:

Getting treatment:

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  Dental care: Brushing and flossing your teeth

Cause

The combination of bacteria and food causes tooth decay. A clear, sticky substance called plaque that contains bacteria is always forming on your teeth and gums. As the bacteria feed on the sugars in the food you eat, they make acids. The acids attack the teeth for 20 minutes or more after eating. Over a period of time, these acids destroy tooth enamel, resulting in tooth decay.

See pictures of a tooth and tooth decay.

You make tooth decay more likely if:

  • You don't brush your teeth twice a day, in the morning and before bedtime.
  • You don't floss your teeth each day.
  • You eat foods with a lot of sugar in them. The longer a sugary food stays on your teeth, the more the bacteria feed and make acids. Sticky sweets and sugary foods, such as raisins, sugar-coated cereal, cake, cookies, caramel, and taffy, cause the most damage.

Lack of fluoride in the public water supply also makes tooth decay more likely.

You can pass the bacteria that cause tooth decay to your baby. This can happen when you share spoons, forks, and other utensils with babies. The saliva you leave on the utensil contains the bacteria. Sometimes kissing can also transfer saliva and bacteria. You can help prevent tooth decay in your child by making sure that your family practices good dental health habits.

Symptoms

Tooth decay usually does not cause symptoms until you have a cavity or infected tooth. When this occurs, symptoms include:

  • Toothache, which is the most common symptom. An infection or irritation of the tooth pulp usually causes the pain.
  • Bad breath or a foul taste in the mouth.
  • White, gray, brown, or black spots on the teeth.
  • Loose fillings.
  • A broken tooth or a tooth that is sensitive to pressure.

The pain may become worse when you:

  • Eat sweets.
  • Eat hot or cold foods or drink hot, cold, or acidic liquids, such as citrus drinks.
  • Chew food or gum.
  • Breathe in cold air.
  • Brush your teeth.

Severe tooth decay may cause a pus-filled sac (abscess) to form in the bone at the base of a tooth. Symptoms of abscess include:

  • Fever.
  • Swollen glands.
  • A swollen jaw.
  • Deep, throbbing pain.

For more information, see the topic Abscessed Tooth.

What Happens

Tooth decay usually happens slowly over a period of months or years.

Decay begins when bacteria in your mouth increase during the first 20 to 30 minutes after you eat. The bacteria make acids, which eat away at the hard mineral layers of the tooth. A hole (cavity) forms when the acids cause more damage than the tooth can repair.

See pictures of a tooth and tooth decay.

A tooth has an outer layer (enamel), a middle layer (dentin), and a center (pulp). The more layers that are affected by decay, the worse the damage.

  • When tooth decay is mild, the area of decay is small and has not pierced the tooth surface. You can sometimes stop the decay with improved care, such as having your dentist apply fluoride to your teeth.
  • When tooth decay gets worse, a cavity forms. You will need a filling to stop the decay and prevent more damage.
  • If the pulp begins to decay, the tooth will likely die, because the pulp contains nerves and blood vessels that supply the tooth. After a decayed tooth dies, an abscess may form in the bone at the end of the root. For more information, see the topic Abscessed Tooth.

Types of cavities (dental caries) are:

  • Pit and fissure cavities, which form in the deep pits and grooves on the chewing and biting surfaces of the back teeth.
  • Smooth-surface cavities, which form on the sides of teeth, including between the teeth.
  • Root cavities, which form on the root and can extend below the gum line. Root decay is less common than decay in other parts of the tooth. But root decay is more likely to damage the tooth pulp.
  • Recurrent or secondary cavities, which form where you already had a cavity.

Untreated tooth decay causes more severe problems and can lead to gum disease. For more information, see the topic Gum Disease.

Your saliva helps prevent tooth decay. It reduces acid damage to a tooth by washing away sticky, sugary foods that feed bacteria. The minerals in saliva also can help repair the tooth.

What Increases Your Risk

The following factors make it more likely that you will have tooth decay and develop cavities.

Factors that you can control include:

  • Your dental care.
    • If you do not brush and floss your teeth regularly, plaque and bacteria build up on your teeth. Brushing your teeth twice a day and flossing once a day helps remove the plaque from the surfaces of your teeth, between your teeth, and under your gums. With less plaque, there are fewer bacteria to make the acids that eat away your teeth.
    • Not having your teeth cleaned by your dentist also allows plaque to build up. Your dentist or dental hygienist scrapes off the plaque and tartar, giving your teeth a "clean start." Regular visits to your dentist for cleaning and checkups can help prevent tooth decay and also catch other dental problems early, before they become serious.
  • Eating foods that are high in sugar and other carbohydrates (pastries, grains, pasta, and bread). Bacteria feed on these types of food, so eating a lot of them speeds up the rate of tooth decay.
  • Lack of fluoride. Fluoride helps prevent tooth decay by making teeth more resistant to acids produced by plaque. If your local water supply does not have enough fluoride in it, use a toothpaste that contains fluoride. Also talk to your dentist or dental hygienist about other ways you can increase your fluoride levels.
  • Smoking, using spit (smokeless) tobacco, or being in areas where you breathe in tobacco smoke (secondhand smoke).
  • Drinking alcohol.

Factors that you cannot control include:

  • Dry mouth (xerostomia) and Sjögren's syndrome. Both of these conditions cause you to be unable to produce enough saliva. Saliva washes away food and harmful sugars and helps protect your teeth from decay. Older adults are more likely to have a dry mouth and more rapid tooth decay because of the dryness. Many prescription and over-the-counter medicines (such as medicines for colds, high blood pressure, and depression) can also cause dry mouth.
  • Age. Young people whose teeth are still growing are more likely to have tooth decay. This is because the minerals in new teeth are not stable and are easier for acids to eat away. Older people may lose more gum tissue and be at a greater risk for root cavities.
  • Respiratory conditions, such as allergic rhinitis, which cause you to breathe through your mouth. When you breathe through your mouth, you dry out the saliva that can help protect your teeth.
  • Certain types of bacteria in the mouth that are more likely to cause tooth decay.
  • Diabetes . People who have diabetes may have an immune system that does not work very well, which increases the risk of tooth decay.
  • Using medicines that contain sugar. The sugar feeds the bacteria. Your doctor may be able to prescribe sugar-free medicine.

Factors that increase an infant's or child's risk include:

  • Going to bed with a bottle of juice, milk, or formula in his or her mouth. The sugar in these drinks feeds the bacteria that cause tooth decay (baby bottle tooth decay).
  • Sharing utensils. Babies are not born with decay-causing bacteria in their mouths. But bacteria are easily transferred from the parent into the baby's mouth through utensils. Sometimes kissing can also transfer saliva and bacteria. You can help prevent tooth decay in your child by making sure that your family practices good dental health habits.
  • Being exposed to tobacco smoke. The chances of a child's developing tooth decay increase with exposure to secondhand smoke.1

When To Call a Doctor

You should make an appointment with a dentist if:

  • You have not seen the dentist in 6 months to a year.
  • You have a toothache. Sometimes a toothache will go away for a while, but the tooth decay will continue. A constant toothache that does not go away could mean that you have severe decay, and you may lose your tooth.
  • You have swelling in your gums near a sore tooth. This may mean that there is severe tooth decay or an abscessed tooth. For more information, see the topic Abscessed Tooth.

Watchful Waiting

Watchful waiting is a wait-and-see approach. If you get better on your own, you won't need treatment. If you get worse, you and your dentist will decide what to do next.

Watchful waiting is not appropriate for a toothache. If you ignore the decaying tooth after the pain goes away, the tooth may become seriously damaged.

Who To See

A dentist is best able to evaluate your tooth decay and pain.

If you have severe decay, the dentist may refer you to a specialist, such as:

To prepare for your appointment, see the topic Making the Most of Your Appointment.

Exams and Tests

When you visit your dentist for tooth decay, he or she will:

  • Ask you questions about your symptoms and past medical and dental problems and care (medical and dental history).
  • Look at your teeth using a pointed tool and a small mirror. Your dentist will look for discolored areas and obvious holes in your teeth.
  • Take X-rays if he or she thinks you have tooth decay that cannot be seen.

Early Detection

Having a dental checkup once or twice a year can help your dentist find tooth decay and other problems before they cause severe problems. If you often have dental problems, your dentist may suggest more frequent visits.

Treatment Overview

Treatment for tooth decay varies according to how severe the decay is.

  • Brushing and flossing with fluoride toothpaste and/or receiving fluoride treatments may be enough to reverse early decay, before cavities have formed. For more information, see:
    Click here to view an Actionset.Dental care: Brushing and flossing your teeth.
  • You need a filling if a cavity has formed. A filling is a material that plugs the cavity hole and restores a tooth to its original shape after your dentist has removed the decay.
  • You may need a crown if the decay is severe and your tooth is badly damaged. A crown (often called a cap) is a man-made replacement for all or part of a tooth. Crowns are also used to treat teeth that have broken or decayed so much that a filling will not work.
  • You may need a root canal treatment if the pulp of your tooth is infected. A root canal removes the diseased pulp of a tooth.
  • You may need your tooth taken out (extraction) if the root of the tooth is severely damaged. You may need to replace the tooth with a bridge or an implant.

If you do not treat tooth decay, your cavities can get worse and you may lose a tooth. If you wait to see your dentist, your tooth repair will probably cost more and take longer.

What To Think About

Many people are very nervous before or during a dental visit. This can make going to the dentist a difficult experience. You can take steps to limit your anxiety, such as explaining your fears to the dentist and setting up a system of hand signals. Hand signals let you tell the dentist when something hurts or you want a break, even if you cannot talk.

Prevention

A combination of bacteria and food causes tooth decay and cavities. You can prevent tooth decay by taking steps to limit the bacteria and by eating healthy foods.

Click here to view an Actionset. Dental care: Brushing and flossing your teeth

Brushing and flossing

Brushing and flossing help limit bacteria on your teeth.

Brushing

  • Get into a routine for brushing. Brush your teeth twice a day, in the morning and before bedtime.
  • Use a toothbrush with soft, rounded-end bristles and a small enough head that allows you to reach all parts of your teeth and mouth. Replace your toothbrush every 3 to 4 months.
  • You may also use an electric toothbrush that has been given the American Dental Association (ADA) seal of acceptance. Studies show that powered toothbrushes with a rotating and oscillating (back-and-forth) action are more effective at cleaning teeth than are other toothbrushes, including other powered toothbrushes.2
  • Use a fluoride toothpaste. Some fluoride toothpastes also offer tartar control, which may help slow the formation of hard mineral buildup (tartar) on the teeth.
  • Place the brush at a 45-degree angle where the teeth meet the gums. Hold the brush firmly, and gently rock the brush back and forth using small circular movements. Do not scrub, because vigorous brushing can make the gums pull away from the teeth and can scratch your tooth enamel.
  • Brush all surfaces of the teeth, tongue-side and cheek-side. Pay special attention to the front teeth and all surfaces of the back teeth.
  • Brush chewing surfaces vigorously with short back-and-forth strokes.
  • Brush your tongue from back to front. Some people put some toothpaste or mouthwash on their toothbrush when they do this. Brushing your tongue helps remove plaque, which can cause bad breath and help bacteria grow. Some toothbrushes now have a specific brush to use for your tongue.
  • Use disclosing tablets every now and then to see whether any plaque remains on your teeth. Disclosing tablets are chewable and will color any plaque left on the teeth after you brush. You can buy them at most drugstores.

Flossing

Floss once a day. The type of floss you use is not important. Choose the type and flavor that works best for you. Use any of the following methods:

  • The finger wrap method: Cut off a piece of floss 18 in. (45.72 cm) to 20 in. (50.8 cm) long. Wrap one end around your left middle finger and the other end around your right middle finger, until your hands are about 2 in. (5.08 cm) to 3 in. (7.62 cm) apart.
  • The circle method: Use a piece of floss about 12 in. (30.48 cm) long. Tie the ends together, forming a loop. If the loop is too large, wrap the floss around your fingers to make it smaller.
  • A plastic flossing tool makes flossing easier. You can find them at most drugstores.

Gently work the floss between the teeth toward the gums. Curve the floss around each tooth into a U-shape, and gently slide it under the gum line. Move the floss firmly up and down several times to scrape off the plaque. Popping the floss in and out between the teeth without scraping will not remove much plaque and can hurt your gums.

You may want to try electric cleaning devices (interdental cleaning devices or interdental brushes) that are made to clean between your teeth. They can be as effective as using dental floss.

If your gums bleed when you floss, the bleeding should stop as your gums become healthier.

Healthy diet

  • Eat many types of food, especially whole grains, vegetables, and fruits, and food that is low in saturated fat and sodium. Good nutrition is vital for children as their teeth develop, and for adults to maintain healthy gums and avoid tooth decay. For nutrition advice, see the guidelines in MyPyramid.
  • Mozzarella and other cheeses, peanuts, yogurt, milk, and sugar-free chewing gum (especially gum that contains xylitol) are good for your teeth. They help clear your mouth of harmful sugars and protect against plaque. These make great after-meal snacks.
  • Avoid foods that contain a lot of sugar, especially sticky, sweet foods like taffy and raisins. The longer sugar stays in contact with your teeth, the more damage the sugar will do.
  • Avoid between-meal snacks.
  • Do not snack before bedtime, as food left on the teeth is more likely to cause cavities at night. Saliva production decreases while you sleep, so saliva does not clean your mouth well during sleeping hours.

Caring for your child's teeth

A child's dental care really starts with his or her mother's healthy pregnancy, because baby teeth begin to form before birth. If you are pregnant, eat a balanced, nutritious diet. And be sure to get enough vitamins and minerals. Pregnant women should have a complete dental exam and get treatment for any cavities or gum disease. For more information, see the topic Pregnancy.

By the time your child is 6 months of age, your doctor should assess the likelihood of your child having future dental problems.3 This may include a dental exam of the mother and her dental history, as the condition of her teeth can often predict her child's teeth. If the doctor thinks your child will have dental problems, be sure your child sees a dentist by his or her first birthday or 6 months after the first primary teeth appear, whichever comes first. After your first visit, schedule regular visits every 6 months or as your dentist recommends.

Experts recommend that your child's dental care start at 12 months of age.3

It's best to start good oral health habits before permanent teeth come in.

  • Parents and caregivers often share spoons, forks, and other utensils with babies. The saliva you may leave on the utensil contains bacteria that can cause tooth decay. In some instances, kissing can also transfer bacteria. You can help prevent early childhood tooth decay in your child by making sure that your family practices good dental health habits.
  • Do not put your infant or small child to bed with a bottle of milk, formula, juice, or any other product that contains sugar. The sugar and acids in these liquids can cause tooth decay (bottle mouth). Do not prop the bottle up in your baby's mouth, and remove the bottle as soon as your baby is done feeding or is asleep. Breast-feeding your infant to sleep is safe.
  • Discuss fluoride supplements with your dentist if your local water supply does not contain enough fluoride. To find out, call your local water company or health department. If you have your own well, have your water checked to determine whether your family needs fluoride supplements. You may also need to provide fluoride to your children if you use bottled water for cooking or drinking.
  • When your child is around 6 years old, consider using a fluoride mouthwash if he or she has a lot of cavities. Be sure that your child does not swallow the mouthwash.
  • Keep your child away from cigarette smoke (secondhand smoke). Tobacco may lead to tooth decay and gum disease.1 As your child grows, teach him or her about the dangers of tobacco and secondhand smoke.
  • Consider having your dentist or dental hygienist put a sealant into the grooves of the chewing surfaces of your child's back teeth to help prevent cavities. Studies show that children who have sealant applied regularly in school-linked programs have a 60% decrease in tooth decay.4

Brushing and flossing your child's teeth

  • As soon as your child's teeth come in, start cleaning them with a soft cloth or gauze pad. As more teeth erupt, clean teeth with a soft toothbrush, using only water for the first few months.
  • After your child is 2 years old, use a green-pea-sized amount (or less) of fluoride toothpaste. Brush your child's teeth for the first few years, until your child can do it alone (usually at about age 3). Teach your child not to swallow the toothpaste.
  • Your child can learn how to brush his or her own teeth at about 3 years of age and should be brushing his or her own teeth morning and night by age 4, although you should supervise and check for proper cleaning. Your child should be able to brush without your supervision by about 8 years of age.
  • Give your child a small, soft toothbrush, and use a green-pea-sized amount of fluoride toothpaste. Encourage your child to watch you and older siblings brush teeth. A good teaching method is to have your child brush in the morning and you brush at night until your child masters the skill.
  • Tips to get your child to brush his or her teeth include setting a good example and having your child brush his or her stuffed animal's teeth.

Because too much fluoride can be toxic, watch that your child does not swallow large amounts. Use caution with fluoride toothpaste or mouthwash for your child's dental care until your child's ability to control swallowing is well developed. Normal amounts of fluoride added to public water supplies, toothpastes, mouth rinses, and bottled water are safe for children and adults.

Dentist appointments

Set up routine visits with your dentist. At the visit, he or she will examine your teeth and gums for signs of tooth decay, gum disease, and other health problems.

For more information about developing good oral health habits, see the topic Basic Dental Care.

A visit to the dentist can be a scary thing for a child. You can reduce this possibility by choosing your dentist carefully and preparing your child for his or her first visit. Call your dentist for ideas about putting your child at ease before you bring him or her in.

Home Treatment

You can take steps at home to relieve pain and swelling in your face and jaw caused by tooth decay.

  • Use an ice pack on the outside of your cheek. Do not use heat.
  • Take an over-the-counter pain reliever. These include:
    • Aspirin. Do not give aspirin to anyone younger than 20 because of the risk of Reye syndrome.
    • Acetaminophen, such as Tylenol.
    • Ibuprofen, such as Advil or Motrin.
    • Naproxen, such as Aleve or Naprosyn.

Medications

Your dentist may prescribe chlorhexidine gluconate (Peridex, Periogard), a prescription mouthwash, to reduce the bacteria that cause tooth decay. He or she may also recommend or prescribe other types of fluoride treatment, such as fluoride mouthwash, toothpaste, or supplements.

Over-the-counter medicine can also relieve pain and swelling in your face and jaw caused by tooth decay. These include acetaminophen, such as Tylenol; ibuprofen, such as Advil or Motrin; and aspirin. Do not give aspirin to anyone younger than 20 because of the risk of Reye syndrome.

Surgery

You may need surgery if tooth decay has damaged the pulp and the tooth.

Surgery Choices

  • In extraction, your dentist removes the decayed tooth.
  • In root canal treatment, your dentist removes the pulp from the center of a tooth and fills the pulp cavity.

What To Think About

After removing your tooth, your dentist will replace it with a bridge or an implant.

If your tooth is severely damaged, it may be easier and may cost less to remove the tooth than to have a root canal treatment. If you have root canal treatment, you will need a crown.

Dental surgery can cause bacteria in the mouth to enter the bloodstream and cause infections in other parts of the body. People who have a difficult time fighting off infections may need to take antibiotics before and after dental surgery. Such people include those who have artificial heart valves or were born with heart defects.

Other Treatment

There is no other treatment for tooth decay.

Other Places To Get Help

Organizations

American Dental Association
211 East Chicago Avenue
Chicago, IL  60611-2678
Phone: (312) 440-2500
Web Address: www.ada.org
 

The American Dental Association (ADA), the professional membership organization of practicing dentists, provides information about oral health care for children and adults. The ADA can also help you find a dentist in your area.


Centers for Disease Control and Prevention (CDC): Division of Oral Health
4770 Buford Highway, NE, MS F-10
Atlanta, GA  30341-3717
Phone: (707) 488-6054
E-mail: OralHealth@cdc.gov
Web Address: www.cdc.gov/OralHealth
 

This Web site offered by the CDC provides knowledge, tools, and networks to promote good oral health and to prevent and control tooth decay, gum disease, and oral cancers.


Know Your Teeth
211 East Chicago Avenue
Suite 900
Chicago, IL  60611-6660
Phone: 1-888-243-3368 ext. 5300
Fax: (312) 440-0559
E-mail: info@knowyourteeth.com
Web Address: www.knowyourteeth.com
 

This Web site by the Academy of General Dentistry provides information on dental care and oral hygiene.


National Institute of Dental and Craniofacial Research (NIDCR)
National Institutes of Health
Bethesda, MD  20892-2190
Phone: (301) 402-7364
Fax: (301) 480-4098
E-mail: nidcrinfo@mail.nih.gov
Web Address: www.nidcr.nih.gov
 

The National Institute of Dental and Craniofacial Research (NIDCR) is a governmental agency that provides information about oral, dental, and craniofacial health. By conducting and supporting research, the NIDCR aims to promote health, prevent diseases and conditions, and develop new diagnostics and therapeutics.


References

Citations

  1. Aligne CA, et al. (2003). Association of pediatric dental caries with passive smoking. JAMA, 289(10): 1258–1264.
  2. Robinson PG, et al. (2005). Manual versus powered toothbrushing for oral health. Cochrane Database of Systematic Reviews (2). Oxford: Update Software.
  3. American Academy of Pediatric Dentistry (2004). Clinical guidelines on infant oral health care. Available online: http://www.aapd.org/media/Policies_Guidelines/G_InfantOralHealthCare.pdf.
  4. Truman BI, et al. (2002). Reviews of evidence on interventions to prevent dental caries, oral and pharyngeal cancers, and sport-related craniofacial injuries. American Journal of Preventive Medicine, 23(1, Suppl): S21–S54.

Other Works Consulted

  • Campbell PR (2009). Carious lesions. In NO Harris et al., eds., Primary Preventative Dentistry, 7th ed., pp. 29–42. Upper Saddle River, NJ: Pearson.
  • National Institutes of Health (2007). NIH fact sheet: Tooth decay.

Credits

Author Jeannette Curtis
Editor Kathleen M. Ariss, MS
Associate Editor Pat Truman, MATC
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer Steven K. Patterson, BSc, DDS, MPH - Dentist
Last Updated July 17, 2009

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